One type of conventional various vehicle lighting units may be one that includes a bent light guiding lens having an L-letter shape bent at a bent portion, and the light guiding lens is illuminated with light to emit light therethrough (for example, Japanese Patent Application Laid-Open No. 2010-003597), as illustrated in FIGS. 1A and 1B.
Specifically, this type of lighting unit, as illustrated in FIG. 1A, can include an elongated light guiding lens having an L-letter shaped cross section. The light guiding lens can have an incident surface at one end of the L-letter shape and a light-exiting surface at the other end thereof. Further included are a plurality of light sources such as light emitting diodes disposed to face to the incident surface. Light emitted from each of the light sources can enter the light guiding lens through the incident surface, and can be totally reflected by the bent portion of the L-letter shape to exit through the light-exiting surface. At that time, the plurality of light sources can be disposed at appropriate intervals therebetween such that the light diffusion ranges of the adjacent light sources can be overlapped with each other in the longitudinal direction, so that the elongated light-exiting surface can be illuminated with uniform light or light can be emitted through the light-exiting surface in a line-shaped manner.
In the aforementioned conventional lighting unit, the light entering the light guiding lens through the incident surface is simply reflected at the bent portion to exit through the light-exiting surface. Thus, the light diffusion ranges from the respective light sources in the longitudinal direction are limited to a certain extent.
As illustrated in FIG. 1B, suppose a case where there is a portion of the light guiding lens that is extendedly formed outside of the light diffusion ranges, specifically, the light guiding lens may have a largely extended end portion of the light-exiting surface relative to the end portion of the incident surface. In this case, the light cannot be properly guided to the extended end portion of the light-exiting surface due to the limited light diffusion ranges, meaning that the extended end portion of the light guiding lens cannot be illuminated with light. As a result, when the lighting unit is installed within a housing (light chamber), it would be difficult to project light with the entire elongated light-exiting surface, which makes the degree of design freedom and marchantability decreased.